Apparatus for supplying air and the like



July 25, 1944. REECE 2,354,276

APPARATUS FOR SUPPLYING AIR AND THE LIKE Filed Feb. 12, 1941 PatentedJuly 25, 1944 UNITED STATES PATENT OFFICE APPARATUS Foa sUPPLYmo Am AND'rns LIKE Herbert A. Reece, Cleveland Heights, Ohio, asslgnor toMeehanite Metal Corporation, a corporation of Tennessee My inventionrelates to supply apparatus for delivery of air and the like tofurnaces, such as metallurgical furnaces.

It has became recognized that the successful operation of furnaceshaving a plurality of tuyeres entering the furnace, such as, forexample, a cupola or other metallurgical furnace, depends to a greatdegree upon the control of the supply of air to the tuyres. The controlof air supply producing the best results is one in which the total airblast to the furnace is under'adequate control and also in which theproportionate air blast to each of the several tuyres is properlygoverned.

Heretofore, the supply of air to the plurality of furnace tuyeres hasbeen accomplished by the use of a wind box functioning as a commondistributing chamber which receives air from a source of an air blast,such as a blower, and supplies the air to the plurality oftuyerescommunicating with the wind box. The use of wind boxes forsupplying air to the tuyeres, however, had certain inherent defects anddisadvantages. For example, the supplyin of air to the several tuyereswas not uniform, the velocity of the air entering the several tuyeresbeing unequal. Also, the supply of the total air blast required in thefurnace was not maintained at the proper rate nor were necessary changesin the operation of the blower to maintain the said proper rateobtainable without a disadvantageous time lag between the requirementsof the furnace and the changes in operation of the blower.

It is an object of the present invention to eliminate the use of a windbox for distributing air to a plurality of furnace tuyeres.

Another object is the elimination of the defects and disadvantagesinherent in supply apparatus utilizing a wind box.

Another object is the provision for supplying each of a plurality oftuyeres with an air blast ers each of which communicates of a pluralityof furnace tuyres.

. Another object is the provision for synchronous operation of a,plurality of blowers delivering air to respective tuyres.

Another object is the provision for synchronously supplying air to aplurality of tuyeres in accordance with pre-determined requirements.

Another object is the provision of a plurality of air supply units for afurnace, each of the units comprising a tuyere and a blower forsupplying an air blast to said tuyere.

Another object is the provision of a plurality uQth one tuyere of airsupply units for a furnace, each of the units comprising a tuyre, ablower for supplying an air blast to said tuyere, and adjustable speeddriving means for said blower.

Another object is the provision of a plurality of air -supply units fora furnace, each of the units comprising a tuyere, a blower for supplyingan air blast to said tuyre, and control means for controlling the airblast output of said blower.

.Another object is the provision for supplying air to a plurality oftuyeres in accordance with the requirements for each said tuyre.

Another \object is the provision for supplying air to a plurality'oftuyres by a blower for each of said tuyeres, the operation of theblowers being responsive to the amount of air being delivered to thetuyeres.

Another object is the provision of apparatus for obtaining uniformvelocities of the air supplied to a plurality of tuyeres.

Another object is the provision of apparatus for maintaining th supplyof air to a plurality of tuyres at a required minimum rate.

Another object is the provision for controlling the air supply output ofblowers delivering air to a plurality of tuyres without appreciable timelag between output bythfiblowers and delivery to the tuyeres.

Other objects and a fuller understanding of my invention may be had byreferring to the followin description and claims, taken in conjunctionwith the accompanyingdrawing, in which:

Figure 1 is a plan view of a furnace upon which my apparatus may bemounted and in addition illustrates a diagrammatical embodiment of myelectrical control arrangement.

Figure 2 is an elevatlonal view of a side of a furnace upon which myapparatus has been mounted but omits a diagrammatic showing of myelectrical control arrangement.

Figure 3 illustrates a modified arrangement of the blower inlet pipes ofthe apparatus shown in Figures 1 and 2, in which the several inlet pipesare joined to have one common inlet.

The illustratory furnace of which the outer wall II is shown in Figures1 and 2 is a cupola furnace having all of the usual parts necessary forthe operation of the same. For purposes of simplicity of illustrationonly the wall on one side of the furnace is shown in Figure 2 inasmuchas a view of the opposite side would be a duplicate of the view. Theupper and lower ends of the furnace in Figure 2 have been removed asbeing not necessary for the disclosure of the present invention.

The illustratory furnace to which my invention may be adapted had aplurality of tuyres l3 (six tuyres in the present example) which are ofequal size and are uniformly spaced around the periphery of the furnacein a plane passing through the lower part of the furnace. These tuyresextend through the wall of the furnace to communicate with the interiorthereof and extend through the furnace wall I I and fire brick lining ifin the form of a port or window. The disposition of the six tuyres i3 isshown in dotted lines in Figure 1.

As shown in Figures 1 and 2, there is a housing or conduit l 4 mountedto the furnace wall, by any suitable means, over the entrance to eachtuyere in such manner that the interior of the housing or conduit I4 isin free communication with the one tuyere with no other tuyre Connectedin direct communication with, and above, eachhousing or conduit [4 is ablower ii, there being one blower for each housing I! and its respectivetuyre. As the blowers I may be of any well known construction and typeit has not been considered necessary to show the internal structure oftheblowers. On the front wall of each housing or conduit ll there is apeep hole I! in alignment with the respective tuyere.

As there are six tuyres in the example furnace illustrated there are sixblowers l6, each blower being adapted to blow air to only one tuyerethrough a respective conduit or housing It. Guide vanes 25 may bepositioned within each conduit or housing ll to properly guide the flowof air to the tuyeres.

Inasmuch as the blowers l6 are positioned adjacent the furnace wall andin close proximity to the tuyres the air does not travel any appreciabledistance before entering the tuyres. Therefore, there is no appreciabletime lag between the delivery output of the blowers and its entry intothe furnace through the tuyres. Any change in the rate of speed or rateof delivery of the blowers is almost immediately reflected in the rateof air supply entering the furnace through the plurality of tuyeres.

An electric drive unit I! is mounted upon the side of each blower i6 bya supporting bracket 2 or other suitable means in such a manner that theblowers are driven by the respective units. Each blower l6 has an inletpipe l8, respectively, which communicates with atmosphere as a source ofair. In the view of Figures 1 and 2 each inlet pipe l8 independentlycommunicates with atmosphere through an opening lta and in the view ofFigure 3 the arrangement is modified to provide that the several inletpipes II are Joined together by a common communicating pipe i! having aninlet 20 open to atmosphere through an opening 20a and thus all have acommon inlet.

To maintain the supply of air to the tuyeres 7a 7 erating systems.

in constant required amounts, a flow meter control device 2| may beincorporated in one of the pipes ll of the apparatus. As the internalstructure and operation of the device 21 are well known the detailedstructure thereof has not been illustrated. Any suitable flow metercontrol device may be utilized in my apparatus, such as, for example,the flow meter control device shown in United States Patent No.1,977,559 issued to Lewis et al. on October 16, 1934. Such devicesindicate amounts of fluid or gas flow by measuring differentialpressures in the line of flow and at the same time operate distantdevices such as motors, valves, switches and rheostats through suitableconnecting means such as mechanical linkages, electrical circuits andfluid op- The requirements for the operation of the distant devices bythe control device is in accordance with an adjustable setting on thecontrol device.

The control device 2| is in communication with one of the conduits i8through which the air passes. The control device may also be connectedwith the conduit on the outlet side of the blower to determine the flowtherethrough. A restricted orifice plate 22 is mounted in the pipe laandpressure communicating pipes 23 connect the control device with theinterior of the pipe I8 on opposite sides of the orifice plate. Thedifferential pressure on opposite sides of the plate, and hence theamount of air flowing through the pipe II, is measured and integrated bythe control device 2|. To compensate for differences in the temperatureand barometric pressure of the air being measured circulating pipes 24by-pass air through the device 2| and suitable compensating mechanismwithin the device 2 accounts for the temperature and barometricpressure.

It may be assumed that the temperature and barometric pressure of airentering all of the inlet pipes II is the same. Upon the assumption thatthe air entering all the inlet pipes I8 is of the same density, the airpassing through one inlet pipe I! may be used as a sample and the onecontrol device II that is connected to the said one inlet pipe may beutilized for uniformly governing the operation of all of the blowers, asfor example, by the circuit arrangement of Figure 2. As all the blowersare of the same capacity a uniform speed of rotation will assure auniform amount of air advanced by all of them.

The arrangement of Figure 3 may also be utilized by connecting onecontrol device 2|, through pipes 23 and pipes 24, with the common inletpipe 20. In this arrangement the amount of total air being advanced byall six blowers as measured at the common. inlet to all the blowers isused for operating the one control device 2| governing the operation ofmy apparatus, for example by using the control circuit of Figure 1.

Figure 1 illustrates a circuit arrangement which may be utilized forsynchronously operating all six blowers at speeds which are adjustablypre-determined and maintained by a control device 2|. As illustrated inFigure 1, a motor 38 drives through a shaft 31 a synchronous transmitteror generator Ila which in turn is connected to drive the left-handblower as indicated by the dotted lines. The synchronous receivers ormotors I! receive electrical energy from the transmitter Ila and areoperated at the same speed. Each of the motors or receivers driverespectively the other five blowers, as indicated by the dotted lines.

In Figure 1, the stators or primary windings 21' of the respectivemotors l1 and the generator IIa are connected by conductors ll, 34 andII with a suitable source of alternating current designated as A, B andC to be energized thereby. The switch 32 is arranged to disconnect theconductors ll, 34 and 35 from the source oi current A, B and, C. Therotors or secondary windings 28 of the respective motors I1 and thegenerator I la are arranged to be electrically inter-connected throughthe plurality of conductors 2|, 30 and 3|. Although the plurality ofmotors and the generators ila comprising stators 21 and rotors 28 areshown as polyphase units, single phase units may also be used in thecircuit. By the arrangement shown in Figure 1 the several rotors 28 areelectrically interlocked to rotate in synchrony and the motors II aretherefore synchronously operated with the generator "a. The blowers Iare, therefore, also operated in synchrony. An example of the manner inwhich such motors may be synchronously interlocked is to be foundinUnited States Letters Patent No. 2,202,421 issued to Harrell et al. onMay 28, 1940,

' which patent also illustrates other circuit ardeterminable rate.

A generator armature 38 is arranged in closed circuit relationshipthrough conductors I! with the armature 36 of the driving motor. A primemover 40 which may be'a motor or other source of power is arranged todrive the generator armature 38 by the shaft 4|.

A field winding 45 for the generator is connected by conductors 50through adjustable resistance windings 46 and 4| and conductors ii to asuitable source of electrical energy. A switch 41 is adapted todisconnect the conductors 5| from the source of electrical energy. Theadjustable resistance winding 46 is arranged to vary the excitation offield winding 45 and thus vary the speed of rotation of the drivingmotor armature 3| at a predeterminable rate. The adjustable resistancewinding 43 may be utilized to adjust the speed of the driving motor inone speed range and the adjustable resistance winding 48 may be utilizedto adjust the speed of the driving motor in another speed range.

The flow meter control device 2i responsive to the amount or weight ofair determined thereby is connected by a suitable connection 49 with themovable part of the adjustable resistance winding 48 interposed in theelectrical circuit of field winding 45. The connection 49 may be amechanical linkage, fiuid drive means, electrical operating means or anyother means for effecting a movement in the adjustable resistancewinding 48 in accordance with the operation or position of the movableparts of the control device 2|. Manipulation of the adjustableresistance winding 48 varies the excitation of the field winding 45 andthus varies the speed of rotation of the driving motor armature 38.

It is therefore seen that the speed of the driving motor armature I6 andconsequently the speed of the blowers II is responsive to the rate oramount of air flow determined by the control device 2i. In operation,the adjustable resistance windings 43 and 46 are set at proper positionto obtain the normal speed desired for the blowers IS in order toproduce the supply of air at the required rate or amount per hour andthe generator Fla and the motors ii are driven as described. The controldevice 2| is set to indicate any variance from that required rate oramount and to operate the connection 49 and adjustable resistancewinding 48 in accordance with such variance. When the control device. 2iindicates that the required minimum amount of air is not being furnishedat said predetermined rate the blowers ll will be speeded up by thearrangement described. When the control device indicates that therequired maximum amount of air is being exceeded then the blowers I8will be slowed down. By this arrangement the speed of the blowers willbe held at the proper rate to assure the supply of air to the tuyres atthe desired amount.

In a control device 2| incorporating compensating means for temperatureand barometric pressure of the air the weight of the air delivered tothe tuyeres by the blowers will be held under close control. With theinter-locking system of Figure 1 all of the blowers will speed up orslow down together and thus assure supplying the air to the plurality of'tuyres at uniform velocities.

Although I have described my invention with a certain degree ofparticularity, it is understood that the present disclosure has beenmade only by way of example and that numerous changes in the details ofconstruction and the combination and arrangement of parts may beresorted to without departing from the spirit and the scope of theinvention as hereinafter claimed.

I claim as my invention:

1. Apparatus for supplying an air blast to a plurality of tuyre meansfor introducing air into a furnace at a plurality of locationscomprising, a plurality of air blowers having air inlets and airoutlets, each of said outlets being in communiction with a respectiveentrance for each tuyre means to supply air thereto, a separate electricmotor for driving each of said blowers, and electrical circuit meansconnecting said motors for synchronizing the speed of the motors, thesynchronous operation of the motors driving said blowers to blow airinto the plurality of tuyre means at substantially equal velocities.

2. Apparatus for supplying blown air to a plurality of tuyere meansentering a metallurgical furnace at recurring intervals around thecircumferential extent of the furnace, comprising a plurality of airblowers mounted upon the said furnace at recurring intervals around thecircumferential extent thereof and positioned adjacent the said tuyeremeans, respectively, for separately blowing air into the said tuyeremeans, driving means for driving said blowers, and means forcollectively governing the rate of air delivery of the plurality ofblowers to assure the supplying of air to the plurality of tuyere meansat uniform velocities.

3. In a metallurgical furnace having a plurality of tuyere means for thesupply of blown air to the interior of the furnace, said plurality oftuyre means being disposed substantially in a horizontal plane passingthrough the furnace and at recurring intervals around thecircumferential extent of the furnace; a plurality of air blowers eachmounted adjacent to a separate one of said tuyre means, respectively,and regularly distributed around the peripheral extent of the furnace;conduit means for conducting blown air in a separate course from each ofsaid blowers to a respective entrance for each tuyre means, and drivingmeans interdependently connected for operating each of said blowers at aspeed relative to the speed of the other blowers to assure the deliveryof a uniform supply of blown air to the plurality of tuyre means by saidblowers.

4. Apparatus for supplying blown air to a plurality of tuyre meansintroducing the blown air into a furnace comprising the combination of aplurality of air blowers mounted to separately blow air into respectivetuyre means, a plurality of electric motors for driving said blowers,respectively, interlocking electrical circuit means for causing saidmotors to operate at related speeds, variable speed operating means foroperating said motors at the required rate of speed, said electricmotors, circuit means and variable speed operating means providing forthe operation of the blowers to supply blown air to the plurality oftuyre means at the required rate and at related velocities.

5. Apparatus for supplying blown air to the interior of a furnace at aplurality of positions around its circumferential extent comprising aplurality of air supplying units positioned at int-ervals around saidfurnace in juxtaposition to said plurality of positions, each of saidunits including: a blower for blowing air, tuyre means for introducingsaid blown air into the interior of the furnace, a separate conduitconnecting said blower and'said tuyere means, and an electric motor fordriving said blower; and means electrically interconnecting saidelectric motors for driving the said electric motors of said units insynchrony to provide for the uniform operation of said air supplyingunits.

6. The combination of a plurality of blowers arranged to provideindependent air supply means for separately supplying blown air to eachof a plurality of tiLYre means entering a furnace, first means foroperating said blowers in unison to uniformly supply blown air to theplurality of tuyere means, second means for adjusting the delivery ofsaid blowers to a pre-determined rate, and third means responsive to theweight of air advanced by a blower for controlling said second means formaintaining the said predetermined rate of delivery to the plurality. oftuyere means.

7. A system for supplying air to a plurality of tuyre means entering afurnace comprising separate air blowing means for each of said tuyremeans, operating means for operating said air blowing means in unison todeliver substantially uniform amounts of air to the tuyre means, andflow meter means responsive to the delivery of air by said air blowingmeansand operatively connected to said operating means to Jointlycontrol said blowing means for maintaining the supply of air to thetuyere means at a predetermined rate.

8. The combination of a plurality of air blowers for supplying blown airto a plurality of tuyere means entering a metallurgical furnace, each ofsaid blowers being arranged to blow air directly to a respective tuyeremeans separately from the other tuyere means, operating means foroperating said blowers, correlating means for collectively correlatingthe rate or delivery of the plurality of blowers, and adjustable meansgoverning said correlating means for adjusting the rate of delivery ofsaid blowers, whereby said blowers supply blown air to the respectivetuyre means at the required rate determined by said adjustable means andat velocities correlated by said correlating means.

HERBERT A. REECE.

